Vibration characteristics of pre-twisted composite blades are analysed using a three-noded triangular cylindrical shell element. The specific example of glass fibre reinforced plastic material is analysed with its material damping. The effect of different parameters such as pre-twist, fibre orientation, skew angle, taper ratio and aspect ratio on natural frequency and system loss factor is investigated. It is found that the maximum fundamental frequency and maximum fundamental loss factor occur at different twist angles and at different fibre orientations. The influence of taper ratio and aspect ratio on 0° and 90° fibre orientations is reported. The effect of skew angle on natural frequency and on system loss factors is seen to be low. © 1993.

S. Mohamed Nabi

Natrajan Ganesan

Damping

Glass fiber reinforced plastics

Mathematical models

Numerical methods

Shells (structures)

Strain

stresses

Structural analysis

Vibrations (mechanical)

Aspect ratio

fibre orientation

Natural frequency

PRETWISTED COMPOSITE BLADES

SKEW ANGLES

SYSTEM LOSS FACTOR

Taper ratio

THREE-NODED TRIANGULAR CYLINDRICAL SHELL ELEMENT

Turbomachine blades

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Vibration and damping analysis of pre-twisted composite blades

Computers and Structures

The effect of fibre orientation and boundary conditions on the vibration and damping behaviour of thin orthotropic triangular plates is studied by using a three-noded triangular plate finite element. Isosceles triangular plates having three different included angles are analyzed. © 1989.

Journal of Sound and Vibration

Vibration and damping analysis of orthotropic triangular plates

A finite element technique has been used to determine the natural frequencies of a pre-twisted and tapered plate mounted on the periphery of a rotating disc. The pre-twisted plate has been idealized as an assemblage of three noded triangular shell elements with six degrees of freedom at each node. In the analysis the initial stress effect (geometric stiffness) and other rotational effects except the Coriolis acceleration effect have been included. The eigenvalues have been extracted by using a simultaneous iteration technique. Computation of frequencies has been carried out for plates of aspect ratios 1 and 2. Other parameters considered are pre-twist, taper, skew angle and disc radius. From the results of computations an extension to the existing empirical formulae derived by Dokainiah and Rawtani [1] has been suggested for computing natural frequencies of rotating pre-twisted and tapered cantilever plates. © 1981.

A parametric study of vibration of rotating pre-twisted and tapered low aspect ratio cantilever plates

Computer Methods in Applied Mechanics and Engineering

Viscous damping approximation of laminated anisotropic composite plates using the finite element method

CISM International Centre for Mechanical Sciences Rotordynamics 2

Damping Properties of Steam Turbine Blades

Journal of Aircraft

Vibratory behavior of twisted cantilevered plates

Journal	Computers and Structures
ISSN	00457949
Open Access	No